Apparatus for closing a filled synthetic material container

ABSTRACT

A method of and an apparatus for closing a filled container of synthetic material, which comprises the steps of producing a forming piece in its formable state, widened under pressure and filled, to the container, then the upper container section is formed to a head by means of a head mold with pinge edges in its closing position. An additional pressure medium is fed into the container, in order to create a predetermined pressure above atmospheric pressure in the container between the pressure filling step and the airtight closing of the container.

I iJnlted States Patent [1 1 3,690,803 Pechtold et al. [4 1 Sept. 12, 1972 [54] APPARATUS FOR CLOSING A FILLED [56] References Cited SYNTHETIC MATERIAL CONTAINER UNITED STATES PATENTS [721 WWW Heinz Pechmld walldlfm 3,079,631 3/1963 Gasmire ..1s/s BB x Odenwald; Gerhard Gold, 8 3,538,543 11/1970 Nataf ..l8/5 BZ gen, both of Germany [73] Assignee: PMD Entwicklungswerk fur Kunst- FOREIGN PATENTS OR APPLICATIONS stoffmaschinen & Co. Canada ..l8/5 KG Ettilingen Baden, Germany P E R b L S I J rzmary xammero ert ptcer, r. [22] Wed: June 1970 Attorney-Ernest G. Montague 2l A 1. No.1 48 76 l 1 pp 57 ABSTRACT A method of and an apparatus for closing a filled con- [30] Foreign Application Priomy Data tainer of synthetic material, which comprises the steps June 23, 1969 Germany ..P 19 31 710.3 .of producing a forming piece in its formable state, widened under pressure and filled, to the container, [52] US. Cl. ..425/326, 425/387, 53/38 th n the upper contain r s tion is formed to a head 51 Int. Cl ..B29c 17/07 y means of a head mold i h ping edges in i clos- [58] Field of Search ..53/39-43,140;- ing Position An additional Pressure medium is fed 18/5 B, 5 F, 5 BE, 5 BZ, 5 BB, 5 BM, 42 D, 42 J, 42 RR; 425/326, 387

into the container, in order to create a predetermined pressure above atmospheric pressure in the container between the pressure filling step and the airtight closing of the container.

3 Claims, 7 Drawing Figures Patented Sept. 12, 1972 .4 Sheets-Sheet 1 l/weniom Patented Sept. 12, 1972 3,690,803

4 Sheets-Sheet 2 Fig. 2

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APPARATUS FOR CLOSING A FILLED SYNTHETIC MATERIAL CONTAINER The present invention relates to a method of and an apparatus for closing a filled container of synthetic material, which is produced of a form piece widened in the formable state in a' forming tool and filled, whereupon a segmented head mold, movable into an openor closing position, with pinge edges in its closed position forms the upper container-section to a head and closes the container airtight.

During closing of such produced and filled containers it is required, to maintain at least partly the pressure above atmospheric pressure obtained in the container during the preceding pressure filling process and not to permit a drop below atmospheric pressure, so that the containers do not collapse due to the occurrence of an inner pressure below atmospheric pressure, thus are deformed.

In the known methods and devices, immediately after the filling of the filling material, the head section of the container and of the form piece, respectively, while still in its formable state, is formed and welded to a head by application of vacuum in the head mold. This has the drawback, that depending upon the type of the filling material and correspondingly at the time of the welding process mostly pressure below atmospheric pressure, at its best, however, atmospheric pressure, occurs, because the worked and heated filling material admixes itself during cooling with the air enclosed in the container. In addition the forming of the container head does not take place in a perfect manner. It is to be added, that the apparatus required therefor, in particular its vacuum pump and vacuum molds, is very expenslve.

It is one object of the present invention to provide a method of and an apparatus for closing a filled container of synthetic material, which is relatively simple and includes technical means, by which during the production of such filled containers a fitting pressure above atmospheric pressure is produced in its inside and can be maintained at least about constant beyond the closing process.

lt is another object of the present invention to provide a method of and an apparatus for closing a filled container of synthetic material, wherein between the pressure filling process and the airtight closing of the container a predetermined pressure above atmospheric pressure is produced in the container by addition of impressing of a pressure medium, by example air, carbonic acid and the like.

By this arrangement it is brought about, that the pressure in the container more or less balanced out with the atmosphere can be brought once more to a predetermined height prior to its closing during the filling process. Preferably, the method step according to the present invention takes place in such manner, that after the pressure filling process the upper container section, which is still in its own heat, within the range of the pinch edges of the head mild, which are at first partly still open are clamped together safe for an inlet channel, whereupon the pressure medium is pressed into the container through this channel and thereafter the container is closed by complete closing of the head mold.

By this arrangement in particular the advantage is obtained, that the predetermined pressure above atmospheric pressure in the container is retained with sufiicient certainty during the following closure process, in order to be in position to predetermine therefrom also the pressure-rest above atmospheric pressure remaining after a pressure drop.

For the performance of the above described method serves an apparatus, wherein, in accordance with the present invention, at least two clamping jaws movable relative to each other are provided, which clamping jaws have in the clamping position engaging clamping edges with at least one passage hole perpendicularly cut out to their longitudinal planeand are movable relative to the segments of the head mold such, that they reach their clamping position timely sooner than the pinch edges of thehead mold reach their closing position.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

FIG. 1 is an elevation, partly in section, of the essential parts of the forming tools for the production and closing of a bottle-like container from a hose-shaped form piece and a driving device for the head mold segments:

FIG. 2 is a top planview of the head mold with three clamping claws in the open position;

FIG. 3 is a top plan view onto the head mold as shown in FIG. 2, yet theclampingclaws being in their clamping position; and

FIGS. 4-7 are a fragmentary elevation, partly in section, of the showing of FIG. 1 with the head mold and the clamping claws in different working positions.

The machine for the continuous production of filled and closed containers of synthetic material from thermoplastic hose material, which in the formable state is widened in a forming tool in the so-called pressure filling process and filled with liquid filling material, whereupon a head mold consisting of two compressible segments force the upper hose section to a bottle-head and which welds airtight by pinging together the hose wall, is known per se and for this reason not shown in the drawing.

As shown in FIG. I, the previously mentioned machine has a forming tool 10, in which in known manner a hose-shaped forming piece inserted in known manner from an extruder (not shown) is formed to a container 11 and simultaneously filled with a liquid filling material. A head mold l2 sits on this forming tool 10, which head mold 12 consistsof two segments 12a and 12b, which are movable from an open position, shown in FIG. 2, relatively into a closing position, shown in FIG. 1. Both segments have pinch edges 12c and 12d surrounding a head mold-hollow chamber 13, which pinch edges are disposed tightly toward each other in the closing position of the head mold segments (FIG. 1) in the vertical center plane M of the forming tools. They have the task, to pinch together and to weld together above the formed container head, the wall of the forming piece which still has its own heat.

Two clamping claws l4 and 15 are mounted for movement towards each other on the segments 12a and 12b in guides 12e and 12f. On the longitudinal edges 14a and 15a of both clamping claws pointing away from the vertical center plane M of the forming tools,

pressure springs 16 anchored in the head mold-segments obtain a grip, which pressure springs 16 have the tendency to retain the clamping claws with a spring force directed towards each other in a position, in which the longitudinal edges 14b and 15b of the clamping claws which point to the vertical center plane M of the forming tools stand beyond the pinch edges 12c and 12d of the head mold-segments. From the head moldsegments extend abutment pins 17 and 18 in slots 14c and 15c of the clamping claws and limit their movement, influenced by the described pressure springs 16, in the direction toward the vertical center axis M. The longitudinal edges 14b and 15b of the clamping jaws 14 and 15 pointing towards each other are formed to clamping edges and have in the center thereof semi circular cutouts 14d and 15d, corresponding with each other, which in case of engaging clamping edges form a vertical extending passage hole.

The movement of the head mold-segments 12a and 12b from their open position into their closed position and vice versa is performed from a schematically shown hydraulic driving device (FIG. 1), indicating only its essential parts. To each of both segments is coordinated a pressure cylinder 19 with two pistons 20 and 21 shiftable into a plurality of positions, and the piston rods 20a and 21a of the pistons 20 and 21 project towards one of the opposite disposed end sides of the pressure cylinder. The one piston rod 20a projecting from the pressure cylinder on the side remote from the head mold 12 is immovably secured by screwing in of the threaded part of the piston rod into a threaded bore of an immovable part 22 of the machine, while the pressure cylinder 19 itself and the second piston rod 210 connected with the corresponding head mold-segment are displaceable in the longitudinal direction. The pressure conduits for the pressure liquid are only partly shown in FIG. 1, of which the pressure conduits 23 and 24 are coordinated to one piston 20 and the pressure conduits 25 and 26 are coordinated to the other piston 21. The piston rod 20a secured to the machine parts 22 is adjustable in longitudinal direction and is secured by a lock nut 27. With this piston rod 20a the pressure cylinder 19 and by means of the second piston rod 21a, the head mold-segment is fixed in its position convenient for the closing position.

It is to be understood that the driving device for head mold-segments 12a and 12b can be operated hydraulically, as well as pneumatically and also mechanically. The operation of the apparatus of the present invention takes place in the following manner:

FIG. 4 shows the working position of the forming tools, after a hose shaped forming piece is formed in the closed forming tool under pressure to a bottleshaped container 11 and has been filled with a liquid filling material. Vacuum half-dishes 28 are disposed above the head mold 12, which vacuum half-dishes 28 keep strictly open the upper, still unformed section of the container. In the driving device disclosed in FIG. 1, both pistons 20 and 21 are pushed up to the separating wall 19a of the two pressure cylinders 19. Now the pressure fluid is pressed through the pressure conduit 24 into the cylinders, whereby the two cylinders as well as the head mold-segments 12a and 12b, which are connected with the cylinders by means of the pistons 21 and the piston rod 21a, are moved for a first step in the direction of the arrows shown in FIG. 5. The clamping edges 14b and 15b of the clamping claws 14 and 15 come into engagement and clamp the container section together disposed therein, which welds itself, due to their own heat, to the clamping stations. The passage hole 14d, and 15d cut out from the clamping edges leaves free thereby an inlet channel 11a (FIGS. 3 and 5) between the clamped container walls.

After this first movement step of the head mold-segments l2a'and 12b, their pinch edges 12c and 12d do not engage each other yet, as is exemplified from the showing of the working position in FIGS. 3 and 5. By the thus formed inlet channel 11a a pressure medium fitted to the filling material, as for example air or carbonic acid, is pressed into the container by means of a mounted blower 29, where upon reaching of a predetermined pressure above atmospheric pressure inside of the container by mechanical or electrical means through control means which are known, and for this reason not shown, the second movement step of the head mold-segments 12a and 12b is released. Now pressure fluid is pressed through the pressure conduit 25 of the pressure cylinders 19, so that in the immovable cylinders the pistons 21 and with the latter the head mold-segments are moved in the direction of the arrows shown in FIG. 6, up to the closing position, in which the pinch edges 12c and 12d come together in the vertical median plane M of the head mold. The container head is to be finally formed and its wall is airtight welded below the clamping claws l4 and 15 still disposed in their clamping position.

For the following opening of the head mold 12, pressure fluid is pressed into the pressure cylinders 19 by means of the pressure conduits 23 and 26, so that both pistons 20 and 21 are pressed again in the direction towards the cylinder-separation wall 19a, and thereby the head mold-segments are moved in the direction of the arrows shown in FIG. 7. Simultaneously, the vacuum-dishes 28 and the forming tool 10 is opened in the direction of the arrows, whereupon the filled and airtight closed container 11 can be removed from the mold.

While we have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limitmg sense.

We claim:

. 1. An apparatus for closing a filled container of synthetic material, comprising a forming tool,

a head mold disposed on said forming tool, and comprising two segments,

at least two clamping claws movable towards each other arranged above said head mold,

said segments having pinch edges surrounding a chamber defined by said head mold,

said clamping claws having in their clamping position engaging clamping edges with at least one passage hole cut-out perpendicularly to their longitudinal plane, and are movable such, that they arrive at their clamping position timely before said pinch edges of said head molds arrive at their closing position,

a driving device moving said head mold in at least two steps from the open position into the closing position, and including an abutment means,

said abutment means limiting the first movement step after the partly closing of said head mold,

said abutment remaining inactive during the second movement step serving the complete closing of said head mold,

said driving device comprising at least one pressure cylinder with two pistons reciprocating therein and movable into a plurality of positions, and

one of said pistons driving said first movement step and being adjustable relative to an immovable part of the apparatus in the direction of the closing movement'of said head mold.

2. An apparatus for closing a filled container of synthetic material produced from a forming piece expanded in its deformable state by pressure and filled up in a forming tool, comprising a forming tool, including means for forming a head and for air-tight closing of said container, comprising, segments of a head form with pinch edges,

a separated driving means for moving said segments of a head form, independently from said forming tool, into an open position or closed position, respectively,

at least two clamping claws disposed, on said segments of said head form, yieldingly in a direction opposite from each other,

said driving means for said segments of said head form moving said clamping claws relative to each other into a clamping position closing said filled container, and 5 said clamping claws having clamping edges engaging in said clamping position, and extending in a direction toward a vertical center plane of said head form and over said pinch edges of said segments and closing said container having a still open head form up to a narrow inlet channel, the latter being formed by a passage hole cut out in said clamping edges, respectively, of said clamping claws. 3. The apparatus, as set forth in claim 2, further comprising spring means for maintaining said clamping claws, in said open position of said head form, projecting beyond said pinch edges, said driving means moving said segments of said head form in at least a first and second moving step from said open position into said closed position, and said driving means including operative abutments for limiting said first moving step after a partial closing of said head form and said clamping edges engaging at the same time. 

1. An apparatus for closing a filled container of synthetic material, comprising a forming tool, a head mold disposed on said forming tool, and comprising two segments, at least two clamping claws movable towards each other arranged above said head mold, said segments having pinch edges surrounding a chamber defined by said head mold, said clamping claws having in their clamping position engaging clamping edges with at least one passage hole cut-out perpendicularly to their longitudinal plane, and are movable such, that they arrive at their clamping position timely before said pinch edges of said head molds arrive at their closing position, a driving device moving said head mold in at least two steps from the open position into the closing position, and including an abutment means, said abutment means limiting the first movement step after the partly closing of said head mold, said abutment remaining inactive during the second movement step serving the complete closing of said head mold, said driving device comprising at least one pressure cylinder with two pistons reciprocating therein and movable into a plurality of positions, and one of said pistons driving said first movement step and being adjustable relative to an immovable part of the apparatus in the direction of the closing movement of said head mold.
 2. An apparatus for closing a filled container of synthetic material produced from a forming piece expanded in its deformable state by pressure and filled up in a forming tool, comprising a forming tool, including means for forming a head and for air-tight closing of said container, comprising, segments of a head form with pinch edges, a separated driving means for moving said segments of a head form, independently from said forming tool, into an open position or closed position, respectively, at least two clamping claws disposed, on said segments of said head form, yieldingly in a direction opposite from each other, said driving means for said segments of said head form moving said clamping claws relative to each other into a clamping position closing said filled container, and said clamping claws having clamping edges engaging in said clamping position, and extending in a direction toward a vertical center plane of said head form and over said pinch edges of said segments and closing said container having a still open head form up to a narrow inlet channel, the latter being formed by a passage hole cut out in said clamping edges, respectively, of said clamping claws.
 3. The apparatus, as set forth in claim 2, further comprising spring means for maintaining said clamping claws, in said open position of said head form, projecting beyond said pinch edges, said driving means moving said segments of said head form in at least a first and second moving step from said open position into said closed position, and said driving means including operative abutments for limiting said first moving step after a partial closing of said head form and said clamping edges engaging at the same time. 